Copper-manganese oxide catalysts prepared by solution combustion synthesis for total oxidation of VOCs
Clarissa Cocuzza, Enrico Sartoretti, Chiara Novara, Fabrizio Giorgis, Samir Bensaid, Nunzio Russo, Debora Fino, Marco Piumetti
Abstract
A set of Cu-Mn oxides was prepared through the simple and effective solution combustion synthesis method by varying the relative amount of copper and manganese. The physico-chemical properties of the samples were investigated through complementary techniques such as N2 physisorption at -196 °C, XRD, HR-TEM, Raman spectroscopy, temperature programmed analyses (H2-TPR, O2-TPD, and NH3-TPD), and XPS. The prepared catalysts were tested for the total oxidation of volatile organic compounds (ethylene, propylene, and toluene). The best performances, in terms of total VOC oxidation, were achieved with a copper content ranging from 15 at.% to 45 at.%. The catalytic test outcomes demonstrate the beneficial effect of acidic sites, oxygen mobility, and redox ability. In particular, ethylene oxidation is mainly favored by oxygen vacancies and redox properties, while propylene and toluene oxidation is mostly enhanced by acidic sites. All the catalysts prepared can totally oxidize the examined pollutants examined below 310 °C. Moreover, the binary oxides exhibit good catalytic stability over a time-on-stream of 7 hours and low water vapor inhibition (5 vol.% H2O in the gas stream).